For example, standard wire mesh baskets can hold 50-200 pounds per foot, depending on the specifications. Material: Steel trays have a higher weight capacity than aluminium or plastic trays. The wire gauge. Estimate physical weight of ladder, perforated, solid-bottom, and wire mesh trays using material density, length, and dimensions. Comply with NEMA and IEC load limits. Fill percentage is checked from cable outside diameter so you can compare cross-sectional packing against side rail depth.